Signaling apparatus for telephone-lines.



No. 648,978. Patented May 8, I900.

F. R. MGBERTY.

SIGNALING APPARATUS FOR TELEPHONE LINES.

(Application filed June 7, 1899.)

(No Model.)

sis-men STATES PATENT OFFICE.

FRANK R. MCBERTY, oE EVANSTON, ILLINo'Is, ASSIGNOR TO THE WESTERN ELECTRIC COMPANY, OF CHICAGO, ILLINOIS.

- SIGNALING APPARATUS FOR TELEPHONE-LINES SPECIFICATION forming part of Letters Patent No. 648,978, dated. May 8, 1900. I Application filed June 7, 1899. Serial N0, '719,659. (No model.)

To all whom it may concern;

Be it known that I, FRANK R. MCBERTY, a citizen of the United States,residing at Evanston,in the county of Cook and State oflllinois, have invented a certain new and useful Improvement in Signaling Apparatus for Telephone-Lines, (Case No. 32,) of which the following is a full, clear, concise, and exact description.

- My invention relates to signaling apparatus for telephone-lines, and more particularly to apparatus for selectively operating any one of a plurality of instruments which are connected with a single electric circuit-for example, ringing-keys forvselectivelytransmitting signals to a substationof a party telephone-line.

My object is to provide means associated with the several ringing-keys of a party-line telephone system for indicating to the operator which one of a particular set of keys has been last operated-that is, for indicating which one of the substations of a party telephone-line has been signaled-so that should it be desired to transmit a second signal to the same station, as when the subscriber has failed-to respond to the first signal, the identity of that particular station upon the party-. line may be indicated to the operator and the proper ringing-key selected Without hesitation or dependence upon memory. a

In party telephone-lines it is common to provide responsive instruments at each of the substations adapted for operation by currents of distinctive character or in circuits capable of permutation to secure diflerent circuits including the different instruments and to provide for the selective actuation of these instruments as many keys as there are stations or instruments, each key being constructed or connected to transmit current or change the circuit connections to determine the actuation of a particular responsive instrument.. In applying the present invention 1 to apparatus of this type an indicator is as-v sociated or connected with each signalinganother key of the group. When furnished with such appliances, an operator is obviously enabled to transmit any number of signals over a particular line at intervals with-- out risk of mistake and without effort of memory. v

A particularly simple and efficient system of selective signaling to which my invention has been applied involves the use of a metallic circuit from the centralstation to the va rious substations, the two sides of the line being normally separate, a separate'return-cir cuit for the line, and polarized signal-bells, two bells of oppositepolarity being included in branches'from eachwire of the metallic circuit. For operating these four bells four keys are employed, adapted to connect with either of the line conductors signaling current of either positive or negative polarity.

In accordance with myinventi on a rotata ble disk is associated with a group of callingkeys connected with a given cord-circuit at the central-office switchboard, said disks carrying a number of'targets corresponding to I depressed by the operator to actuate the key.

The rotatabledisk, which is placed near them, isprovide'd with openings'through which wedges upon the plungers or buttons of the keys are adapted to pass torotate the disk, the relation of the wedges and'openings being such that the depression of any key rotates the disk into a particular posi-- tion determined by the slope and breadth of the wedge associated with that key, the wedges, and consequently the positions assumed by the disk, being different for difierent keys. The disk carries four targets movin g past four windows corresponding to the keys, the arrangement being such that only Vation of the same.

one target may be seen at a time. The depression of any key causes the target to appear at the corresponding Window. The depression of another key elf-aces this signal and causes a target to appear at another window associated therewith. In atelephone-switchboard a set or group of such keys is placed in the circuit of each pair of connectingplugs, so that when a connection has been established with a party-line by means of the plug-circuit and the required key has been operated to senda call-signal the visible target of the keys in that circuit denotes the station whichhas been signaled and is in use. i In the drawings,'Figure 1 is a plan view of the keys and indicator. Fig. 2 is a side ele- Fig. 3 is a horizontal sectional View on line 3 3 of a portion of the apparatus. Fig. 4 is a vertical sectional view of the device, taken on line 00 m. Fig. 5 represents the disk carrying the targets and the plungers of the keys laid out in a horizontal plane to show the relations of the wedges to the plungers and openings of the disk; and Fig. 6 is a diagram representing a party-line with four stations terminating in a springjack at the telephone-switchboard of the central office and a pair of plugs with their cord-circuit, switch-keys, and accessories.

Similar letters and figures of reference are used to designate the same parts wherever they are shown.

The device shown in Figs. 1 to 4 is a group of foursimilar keys to, b, c, and d, of ordinary character, operated by separate buttons as sociated with a single indicator or registering device. These four keys are fixedtoa common base 6. Each key comprises a pair of switoh-springsfandf, with their normal resting-anvils f and f and alternate contacts f f and a spring-retracted plunger f adapted to be thrust between the curved extremities of the switch-springs to alter their position, the plunger being furnished with a button or push The parts are carried by a block J, of insulating material, which is fixed to the base-plate e. The keys are arranged at equal distances from each other and from the center of the plate e. Above the base-plate e is a disk 9, perforated by four openings or windows a, b, c, and d,respectively, a window appearing near each button. Between the disk or cover g and the base-plate c is a disk 7t, pivoted at the center of plate 6. This revolving disk h has four targets (6 b 0 and d in position to appear-at the windows a b c d as the disk is rotated, the targets being disposed about the disk so that only oneot' them can appear at a time. The windows are spaced ninety degrees apart. The target I) is then spaced an angulardistance from target a equal to ninety degrees plus the'width of a window. Target 0 is placed an equal distance in advance of target I) and target 01 an equal distance in advance of target 0 Thus if the window subtend ten degrees the center of target 5 will be one hundred degrees from the center of a 0 will be two hun dred degrees from a and (1 will be three hundred degrees from a When the targets are thus spaced, obviously two of them cannot appear simultaneously.

The disk 72. is perforated by four rectangular openings a b c d at equal distances from its center, through which pass the stems of the plungers of the keys. Each of these openings has an angular width equal to thrice the angular width of a windowthat is, thirty degrees plus the angular width of the plunger of the key which passes through it, the

latter being perhaps fifteen degrees, making forty-five degrees in all. The openings are spaced about the center of the disk at equal distances.

The plungers of the four keys a, b, c, and d carry cams or wedges 0., b 0, and d of the same width as the openings a b 0 and d adapted to register with the sides of these openings. The wedge a is placed on one side only of its plunger, extending at its thickest portion, as stated, to a distance therefrom equal to thirty degrees on the circle through the openings 19 0 d". Forconvenience the width of wedge corresponding to the angular width of one window-ten degreesmay be termed a step and the movement which is imparted to the disk through the agency of this wedge a stage of the travel of the disk. The wedge a then projects three steps from its stem. The wedge 19 is of equal total width, but projects from the stem one step in the direction of keyaand two steps in the direction of key.

0. Wedge 0 extends two steps toward key I) and one step toward key (I. WVedge dlies altogether on the side of its stem toward key ICC c. The relative arrangement of parts of this contrivance and its operation maybe bestseen in the diagrammatic sketch, Fig. 5. In the figure the target-disk is in the posit-ion in which it was placed by the depression of key (1. Obviously the downward movement of this wedge a would bring the opening or recess a into coincidence with the wedge. The target a should then appear at the window a. All the other targets are concealed.

Now if the key I) be operated the upper'step of wedge M will engage recess b aud will rotate the target-disk backward through one stage of ten degrees, whereby the target a will be withdrawn from coincidence with window a and target I) will be displayed at window Z2, corresponding to the key depressed. If nowkey c be pressed, the target-disk will be moved through an additional stage and target 0 will appear, and finally the operation of-key (Z will revolve the target-disk still another stage and will bring target (I into View. It is clear that the manipulation of the keys need not take'place in this order, however. If, for example, while the device is in the position shown key 0 be pressed, the disk will be moved backward or to the left through two stages and target 0 will ap pear. The subsequent movement of key b will move the target-disk forward one stage, so that target 19 will be seen, and then the use of key at will bring target d into view. Thus in Whatever order the keys may be used the depression of any key will bring into View a target at acorresponding window, and the target will remain in view until the subsequent use of another key. The target-disk, with its targets, is an indicator which is set in the operation of any key to denote the keyused and retains its special significance until it is set to another position in the use of another key.- In the use of these keys and the register in association with the system of selective signals mentioned (represented in diagram Fig. 6) the members of the different pairs of switch-springs and their rest-ing-anvils of the four keys a, b, c, and d are connected serially in the two conductors 1 and 2 of a plug-circuit, uniting plugsil and i. The alternate anvils f of keys aand b are grounded, while the anvilsf' of the same keys are connected, respectively, with the sources of signalingcurrent of oppositepolarity. The anvils f of keys 0 and d are grounded, and the anvils f are led to the same sources of current. In practice the current-supply may be a generator 70, having one terminal grounded and having two contact-springs, to which intermittent or pulsating currents of opposite polarity are delivered.

The selective-signaling instruments employed in this system are polarized bells, to whose armatures a bias or tendency to remain in one position is imparted by light springs. Four such bells are located at four stations A, B, O, and D. The bells at stations A and Bare included in ground branches from one conductor 3 otthe line-circuit. The bells at stations 0 and D are in similar branches from the other conductor of the line. The bells at stations A and O are constructed to ring when traversed by positively-directed current and those at stations B and D only when excited by current of the other direction. It is plain that a bell at any station and at that station only may be operated by applying to a particular line conductor a source of current of particular polarity. The line-wires are led at the central station through the usual spring-jack Z, annunciator on, and battery n. The annunciator is operated by the-closing of a bridge containing the telephone at any substation of the line. Atter the plug 2' has been inserted in spring-jack Z in the usual process of making connection with the telephone-line the depression of any of the keys a, b, c, or (1 will operate the bell at the corresponding station A, B, G, or D. Thus if key a be used a positively-directed current will flow to line conductor 3 and thence to earth at stations A and B, operating the bell at the former station, but notthat at the latter.

these keys in selectively signaling a correspondin g station sets an indicator,which con- To reiterate, the use of any of' stitutes a record of the signal sent, by means of which the operator is enabled to repeat the signal without mistake.

It is evident that the contrivance of this invention may be applied without modification to any set or group of keys whose individual movement it is desired to register and that it may be easily modified to adapt it to any group of instruments or devices for transmitting distinotively-modified currents or for effecting permutation of circuits to permit the selective operation of instruments.

Having thus described my invention, I claim as new and desire to secure by Letters Patent the following:

1. 'The combination with a system of instruments adapted for selective operation, and a group of appliances, one for each such instrument, each adapted to determine the operation of a particular instrument, of a movable part 72. adapted to display a distinctive target or indicator for each of said appliances, and mechanism actuated in the use of any one of said appliances adapted to move said part to display the corresponding indicator and to conceal the indicators of the other appliances, as described.

2. The combination with a system of instruments adapted for selective operation, and a group of appliances, one for each such instrument, each adapted to determine the operation of a particular instrument, a rotatable disk adaptedto display atarget or indicator corresponding to each of said appliances, openings in said disk, and'wedges, one associated with each of said appliances for en-- gaging with the said openings to rotate the disk, each of'said wedges being adapted to rotate the disk through a different and characteristic are, whereby the actuation of any one of said appliances causes the display of the corresponding indicator and the concealment of the indicators of the other appliances, as described.

3. The combination with a group of pushers or plungers, of wedges carried by the plungers, a rotatable target-disk having perforations or openings adapted to register with the wedges, each wedge being adapted to move a target-disk to a distinctive position, and eachv target being adapted to be displayed when a corresponding wedge is operated, as described.

4. The combination with an electric circuit and a plurality of responsive instruments connected with said circuit and adapted for selective operation by electric currents of distinctive character,a group of keys,each adapted to transmit over said circuit current adapted to actuate a particular one of said responsive instruments, a movable part associated with said keys and carrying a number of targets, one for each key, target openings or windows wherein said'targets are adapted to be displayed, and mechanism associated with each of said keys for moving the part through.

a distinctive and characteristic arc, whereby tion with the telephone-line, a group of ringing-keys associated With said cord-circuit, one for each substation, means, controlled by said ringing-keys, for transmitting over the telephone-line electric currents of a character to operate any one of said responsive instruments according to the key operated, a rotatable disk, means associated with each of said keys for rotating the disk a characteristic distance, and indicators, one for each key, adapted to be set by the rotation of said disk, whereby the actuation of any key causes the display of acorresponding indicator and the concealment of the other indicators, substantially as set forth.

In Witness whereof I hereunto subscribe my name this 17th day of May, A. D. 1899.

FRANK R. MOBERTY. Witnesses:

DE WITT O. TANNER, GEORGE P. BARTON. 

